Barometer.



53 pins 7 are included UNITED- s'rrirns P TE T EPIC,

moon NELSON,

OF CHICAGO, ILLINOIS, ASSIGNOR TO EDWARD P. MARTIN COMPANY, OF

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BAROMETER.

Specification of Letters Patent.

Patented Sept. 29, 1908,

Application filed November 5, 1906. Serial No. 341,978.

all whom it may concern:

1 Be itknown that I, JACOB NELSON, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Imrovements in Barometers, of which the folowing isaspecification.

. Thisinvention-relates to means for adjusting the level of the mercury in the barometer cistern with relation to the, zero line, and it refers particularly to an improved means for accurately determining when such adjustment is obtained.

In the accompanying-drawings, Figure 1 is an elevation of a barometer embodyin the features of my invention. Fig. 2 is an e evation, upon an enlarged scale, of the lower portion of said barometer. Fig. 3- is a sectional ilgiewtaken on the plane of dotted line 3 3 of My invention is herein shown as applied to a mercurial barometer comprising 3, barometer tube 1 slidably mounted within loops 2 upon the base 3. The lower end of said tu e isbent to provide a short vertically-extending tube 4, the-upper end of which .is enlarged to form a cistern 5. Upon the face of the base 3, near its upper end, and behind the barometer tube 1 is securcd a plate 6 which is graduated at one side of said tube in tenths of inches, and at the other side in millimeters.

The poin'tfromwhich the height of the mer-.

curial columnis measured, or zero, 1s marke by two contact ins 7 mounted upon the base 3 by means to y e hereinafter described, said pins extending vertically through the open upper end of the cistern 5. The lower ends of said pins are platinum points secured to an insulating 8., The contact pins 7 are block 9 in this instance by means of binding posts 10. The insulatingblock 9 is removably secured to the base .3 preferably by means of a clamping screw 11 extending through an elongated opening 12 in said base into a screw-threaded bushing 13 fixed in an opening 14 in said base. In the present embodiment the insulating block 9 is positioned on the base 3 bymeans of two brass taper pins '1 5 adapted to extend through an opening 16 in each end of said insulating block into brass bushings '17 secured in openings 18 in the base.

*When the barometer is in use, the contact in an. electric circuit which tapered and terminate in rise wires 19, a battery 20, and an electriesignaling device 21. Said signaling device may be of any common or preferred type, such as a lamp, bell, buzzer or the like. The wires 19 are connected with the contact pins 7 by means of the binding posts 10.,

As hereinbefore stated, the lower extremities of the contact ins 7 mark the place from which the heig t of the mercurial column is measured. 1 The .means for moving the cistern 5 to bring the surface of the mercury in said cistern into register with this zero point or line, may be of any desired construction. In the example shown in the drawings, said moving means comprises a bracket 22 having an elongated opening 23 in its upper portion through which a securing screw 24 extends. The lower portion of s'aid bracket is slidably mounted within a clip 25 secured to the base 3. A piece 26 is fixed to may com the bracket 22 and affords a support for the tube 1.

in the clip 25 extends an adjusting screw 27 Through a screw-threaded opening rotatably connected with the bracket 22. When said screw is rotated, thebracket 22 and the barometer tube 1 are moved up or down, as the case may be.

In operation, the contact pins 7 are included in an electric circuit as hereinbefore described, and the barometer tube 1 adjusted in position by means of the thumb screw 27 until the surface of the mercury in the cistern 5 is brought to the zero point or line indicatcd by the lower extremities of said contact pins, whereupon a circuit is closed through the mercury, actuating the signaling device 21., and informing the operator that the instrument has been adj ustcd to zero.

In order that the contact pins 7 may be withdrawn from the cistern 5 face of the mercury in the cistern has been adjusted to zero, they are mounted upon a block movably secured to the base 3 by means of the clamping screw 11 and taper pins 15 as described. When the taper pins 15 are withdrawn from their openings, and the clamping screw 11 loosened, the block 9 may be lifted vertically to withdraw the pins 7 from the cistern 5. T he tape-r pins 15 pro-- vide convenient means for accurately positioning the lower extremities "of the contact pins 7 "with reference to zero.

While I have described in some detail a specific embodiment of my invention which I deem to be new and advantageous in the dcwhcn the suri tails of construction, I do not Wish to be understood as limiting myself, in respect to the broader features of my invention, to the specific-construction herein set forth.

I claim as my invention:

1. In a barometer, in combination, a barometer cistern; two contact pins arranged to extend into said cistern, the lower ends of said pins indicating the zero line; means for adjusting the position of said cistern to move the mercury therein into contact with said pins; a signaling device; and an electric eir cuit including said contact pins and said signaling device.

2. In a barometer incombination, a barometer cistern; a base upon which said cistern is mounted; two contact pins arranged to extend into said cistern, the lower ends of said pins indicating the zero line; an insulating support for said pins movable to carry said pins into and out of operative position; means for accurately positioning said pins in operative position; means for securing said pins in operative position; a signaling device and an electric circuit including said'contaet pins and said signaling device.

3. In a barometer, in combination, a berometer cistern; a base upon Which said cistern is mounted; means for adjusting the position of said cistern; an insulating blockliaving an elongated opening therein; a clamping screw extending through said opening into said base for securing said block to said base; two contact pins attached to said block and arranged to extend into said cistern for indicating the zero line, said block and saidbase having openings formed therein arranged to register when said )in's are in zero-indicating position; a tapered positioning pin adapted to lie in said openings for positioning said contact pins; a signaling device and an electric circuit including said contact pins and said signaling device. i

JACOB NELSON. lVitncsses:

MATILDA M. DA iiY, GEORGE L. CHINDAHL. 

